The invention relates to disintegrating substrates such as wipes.
Efforts have been made to develop disposable products such as diapers and personal care items that can be discarded by flushing them down a toilet. One area of focus in this effort has been the binder that is used to bind together the fibers that are used in disposable products. The binder must have sufficient strength to hold the fibers together during storage and use yet lose strength when placed in water.
Binders that have been proposed for this purpose have been formulated with polymers that are soluble in cold water, such as the water found in a toilet, but insoluble in warm water. Other binders have been formulated with polymers that are sensitive to ions. The ion-sensitive polymers, when placed in an aqueous medium, are sensitive to a change in the concentration of ions in the aqueous medium. Some ion sensitive polymers are insoluble in aqueous solutions that have a high concentration of salt but soluble in aqueous solutions that have a low concentration of salt. The theory is that if the polymer is soluble in a solution with a low concentration of salt, such as water, then the polymer will dissolve once it is in contact with water. If the binder dissolves, then it will no longer be able to function as a binder and will lose its “binding” properties. As a result, an article constructed with such a binder may break apart when placed in toilet water and be capable of being flushed down the toilet.